February 8, 2002

Technological advances spark neurosurgery

Featured Image

Dr. Pete Konrad, assistant professor of Neurological Surgery, employs the MicroTargeting Platform during deep-brain stimulation. VUMC was the first major medical center to use the device. (photo by Dana Johnson)

Technological advances spark neurosurgery

The small, custom-fit tripod of the MicroTargeting Platform replaces the bulky, burdensome “halo” frame that has to be anchored to the operating table.(photo by Dana Johnson)

The small, custom-fit tripod of the MicroTargeting Platform replaces the bulky, burdensome “halo” frame that has to be anchored to the operating table.(photo by Dana Johnson)

The excitement of two surgical “firsts” mingled in the near-sterile air of OR 14 recently as a neurosurgery team went busily about the various tasks of implanting two deep-brain stimulators, one into each hemisphere of Jennifer Allison’s brain to stop the quaking tremors and frozen state of Parkinson’s disease.

Both of the firsts should help relieve patient headaches; one by increasing and smoothing access to the deep-brain stimulator procedure, the other by literally making the patient more comfortable during the 6-8 hour surgery.

On Jan. 12, Vanderbilt became the first major medical center in the country to offer patients such as Allison a revolutionary device. The MicroTargeting Platform, designed by FHC, a small company in a tiny town in Maine, is a custom-fit tripod not much larger than a hand that anchors to the patient’s head and allows precision placement of electrodes into the target brain tissue, where faulty firing sparks the tremors.

“When you bring groups like FHC and Vanderbilt together like this it creates a synergism that’s really exciting,” said Dr. Pete Konrad, assistant professor of Neurological Surgery, still riding the buzz several days after Allison’s surgery. “We are now perched as the leader in deep-brain stimulation.”

Allison also was the first patient at Vanderbilt to receive bilateral stimulators following FDA approval of the two-shot strategy for Parkinson’s disease. Vanderbilt was among the first medical centers in the United States to study the use of deep-brain stimulators, both unilaterally and bilaterally, said Dr. David Charles, assistant professor of Neurology, who programs the leads in stimulators such as Allison’s.

Prior to the FDA blessing, insurance companies fought payment, creating a long debate that kept some patients waiting a year or more for the surgery, Charles said. The approval should eliminate that battle and create the opportunity for many more patients to receive them.

“This opens up the shop” to more patients, Konrad said. He estimates 10,000 to 20,000 people are candidates for the stimulators, and expects to stay busy with about one procedure a week now.

The FHC platform’s “frameless technology” weighs about 3 ounces and replaces the bulky, medieval-looking “halos,” the 5-10 pound stereotactic frames that screw to the patient’s head, then to the operating table for support. The first FHC platform was used in a small hospital near FHC headquarters in December. But last year company representatives approached Konrad at a meeting, wanting to marry their technology to one of Vanderbilt’s creations: bone markers, plastic posts screwed into the patients skull that become fixed reference points for planning the operation.

The halo has to be fitted to the patient in the OR in what can be a long and tedious process. With the FHC device, the patient comes in a week before surgery to have the bone markers fitted as an outpatient procedure. CT and MRI images are combined, Konrad plans the trajectory of attack and sends the data to FHC, where a MicroTargeting Platform is custom made for the patient.

In the OR, the bone markers become anchors for the platform.

“The basic concept is to find a target in the brain,” said Ron Franklin, director of technical development at FHC. “Our thought was if you know a target and have an instrument that can reach the target and can hold the instrument in space, then it’s possible to build a customized fixture between the target and the instrument that holds it at a known distance and a known orientation from the target.”

The platform holds steady the electrodes in relation to the brain, Konrad said. Patients can move their heads. The patient in Maine “got up off the table and walked around so doctors could test his gait,” Franklin said. Manufacturing improvements in the past two to three years have made production of the device—made from nylon-like glass-filled powder—economically feasible, he said. “We can turn one around in about two hours, but for now we’re spending about a week on one.”

Allison, diagnosed with Parkinson’s disease in 1994 at age 38, also was excited about the surgical firsts. “Without medications, I can hardly do anything,” she said. Going through the surgery created its own anxiety, and the thought of having a multi-pound frame screwed to her head compacted Allison’s worries. “The pictures I saw of the old head frame were pretty scary, and the surgery is bad enough,” she said. With the halo, Allison said, “I probably would have jumped off the bed and said, ‘enough of this.’” The surgery still was long, she said, but after the stimulators are turned on and adjusted, she hopes to be climbing mountains with her family.

“I hope (doctors) learn a lot from this, and other people can take advantage of it,” Allison said.

Yet another first in Allison’s surgery was a teleconference of the operation with FHC. Franklin and others at the company watched live as the team used their device.

“Teleconferencing makes collaborations such as this one easier and more efficient, which helps us build stronger relationships with companies like FHC,” Konrad said.

Neurosurgery also got a boost from an OR equipment overhaul. New “surgical navigation technology,” called the Stealth Treon System, was installed in December, and should not only bring more efficiency and versatility to the OR, but, Konrad says, it will be an essential equipment cornerstone for building the department.

“With this acquisition we can integrate more features and be more adaptable,” Konrad said. “We can also build a relationship with the manufacturer (Medtronic) that will allow us to grow research programs with them.”

The new system includes navigation capabilities for almost every kind of neurosurgery, Konrad said, and upgrades by the company let the surgeon track instruments by mapping in real-time the location of the instrument in relation to CT and MRI images. And, Konrad said, this is yet another attraction for recruiting top-flight neurosurgeons. “This brings Vanderbilt to the technological forefront,” he said.